Science experiments
and robotic arm operations were the focus for Expedition Four Commander
Yury Onufrienko and Flight Engineers Dan Bursch and Carl Walz aboard
the International Space Station this week.

The crew began
the week by bringing the Active Rack Isolation System back to life after
installing a new shock absorber in the rack. One of the eight pushrods
that was not operating correctly was replaced by the crew. The system
works to dampen out the vibrations generated by crews’ movement throughout
the station. Those vibrations could affect the delicate science experiments
located inside the rack. Air and water samples were taken from the Advanced
Astroculture experiment inside the US Destiny laboratory. The samples
will be brought back to Earth for scientists to study. Scientists hope
to determine what nutrients and conditions are necessary for plants
to grow in microgravity.

The Earthkam experiment
was activated once again this week. The crew set up a digital camera
in the window of Destiny, enabling middle school students on the ground
to remotely take pictures of the Earth’s geographical features from
a vantage point 240 statue miles high.

To prepare for
the Earthkam activation, the station’s robotic arm was moved Tuesday
so it would not block the view of Earth from the Destiny lab. The crew
could not release the brakes to begin the move using the arm's primary
avionics system. The secondary avionics system operated normally, however,
and was used to perform the move. The specific cause of the problem
with the primary avionics system is still being investigated.

Thursday, the crew
put the arm through a practice run of the movements it will make during
the next shuttle mission to the station, STS-110 in April. The arm will
be used to attach the next major station component, the S0 truss. On
Thursday, ground controllers also sent up tests for the primary and
secondary computer workstations used to operate the arm. The secondary
workstation was not able to boot up during the test, and engineers are
evaluating it. When the workstation difficulties were encountered, the
arm was left in a safe parked position while engineers study the problem.

Information on
the crew’s activities aboard the space station, future launch dates,
as well as station sighting opportunities from anywhere on the Earth,
is available on the Internet at:

The next ISS status
report will be issued March 15, or sooner, if developments warrant.

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